Hybrid photonic/plasmonic ZnO/Au composites for sensing applications

We have studied the enhancement factors (EF) in Surface Enhanced Raman Scattering (SERS) substrates prepared with self assembled ZnO nanorod arrays and Au nanocrystals. The ZnO/Au composite nanoarrays present experimental EF values as high as ∼0⁷ for detection of Rhodamine 6G (R6G) using an excitation wavelength of 633 nm. We have study the EF via numerical simulations of a single ZnO/Au composite nanorod using a FDTD algorithm. Our results indicate that the coupling between the photonic wave guiding in the ZnO nanorod and the plasmonic resonance in the Au nanocrystals plays a significant role in the observed EF and need to be considered to fully understand and optimize the development of high efficiency, reproducible, and stable SERS substrates.